FairyGUI.Shape.HitTest C# (CSharp) Method

        protected override DisplayObject HitTest()
        {
            if (_type != 3)
                return base.HitTest();
            else
            {
                Vector2 localPoint = WorldToLocal(HitTestContext.worldPoint, HitTestContext.direction);
                if (!_contentRect.Contains(localPoint))
                    return null;

                // Algorithm & implementation thankfully taken from:
                // -> http://alienryderflex.com/polygon/
                // inspired by Starling
                int len = _polygonPoints.Length;
                int i;
                int j = len - 1;
                bool oddNodes = false;

                for (i = 0; i < len; ++i)
                {
                    float ix = _polygonPoints[i].x;
                    float iy = _polygonPoints[i].y;
                    float jx = _polygonPoints[j].x;
                    float jy = _polygonPoints[j].y;

                    if ((iy < localPoint.y && jy >= localPoint.y || jy < localPoint.y && iy >= localPoint.y) && (ix <= localPoint.x || jx <= localPoint.x))
                    {
                        if (ix + (localPoint.y - iy) / (jy - iy) * (jx - ix) < localPoint.x)
                            oddNodes = !oddNodes;
                    }

                    j = i;
                }

                return oddNodes ? this : null;
            }
        }